National Harbor, MD — Libertarian Sen. Rand Paul stole the show from under Sen. Marco Rubio’s nose at the opening session of the Conservative Political Action Conference, criticizing a “stale and moss-covered” GOP and calling for a new focus on liberty.

The back-to-back pairing of Rubio and Rand was seen as the most significant matchup of the annual conference, pitting two likely 2016 Republican contenders before the party’s conservative base. The result pointed to the growing schism in the Republican Party between resurgent libertarians and more traditional Republicans.

The two men -Paul age 50, Rubio just 41- laid out divergent visions of an inclusive Republican Party. Rubio called for a focus on economic opportunity and a muscular role overseas. Paul called for a reduction in the size of the U.S. government at home and abroad.

Speaking first, Rubio railed against China in a case for continued American leadership in the world, warning of anti-democratic and anti-dissident actions, including cutting off access to the Internet and forced sterilizations.

“This is what they do to their own people,” Rubio said. “We want that to be the leading country in the world? …That’s what’s at stake in America’s greatness.”

Minutes later, and with hundreds standing attentively listening to his every word, Paul echoed his warnings about drone strikes that earned him national fame last week for his 13-hour filibuster.

But Paul, whose supporters flooded the standing-room-only ballroom audience with thousands of “Stand with Rand” posters and stickers, went further, calling for the Republican Party to shift away from neoconservative foreign policy. He warned that the Republican Party is “encumbered by an inconsistent approach to freedom.

“The GOP of old has grown stale and moss-covered — I don’t think we need to name any names, do we?” he said, though the target, Sen. John McCain, was clear.

‘The new GOP,” Paul said advocating for a smaller U.S. presence abroad and a smaller government at home, “will need to embrace liberty in both the economic and the personal sphere. If we’re going to have a Republican Party that can win, liberty needs to be the backbone of the GOP.” He pledged to introduce a budget in the coming weeks to balance the budget in five years that would also slash the income tax in half, and create a flat tax at 17 percent.

The contrast between the pair couldn’t be more obvious or consequential for the party struggling to remake itself after two straight presidential defeats.